This application seeks support to establish a Data Coordinating Center (DCC) for the Consortium for Identification of Environmental Triggers of Type 1 Diabetes. The DCC will play an active role in the development of study protocols and the data management and analysis necessary to support them. Working with the Clinical Centers, the DCC will provide expertise regarding alternative study designs to achieve stated objectives. It is conceivable that case-control, case-case and cohort designs may all be considered to address certain objectives in at risk populations. Issues regarding matching and the selection of controls, as well as the logistics of recruitment and retention are all salient to decisions regarding feasible study development, design and implementation. The DCC proposes to be active on the Consortium Steering Committee and work closely with CC directors to establish the protocol(s) to be followed. The DCC will develop subcontracts for central laboratories and monitor their performance. The DCC proposes to develop a comprehensive Manual of Operations to serve as a reference document for all Consortium members. The manual will provide key definitions and procedures for recruitment, retention, laboratory measurements, training, data acquisition and flow. A Consortium web site will be established. It will contain the Manual of Operations along with current versions of all study data forms and approved study protocol(s). The web site will provide both the ability to collect data on-line and also a study management area that contains key study documents and committee reports. Within the Manual of Operations web page, it is possible to access the entire manual as a single document, access each section independently, or search for key words. Each section of the manual is dated so that study participants can identify the correct version of the manual and keep track as to when modifications are made. In this way, the most current manual (as well as protocol and data collection forms) is available to the entire Consortium. The DCC will also develop a Manual of Operations for its own internal functioning as it has for both the Diabetes Prevention Trial-1 and the international TRIGR study. This version will document all DCC procedures for data collection, transfer, quality control and data management and reporting.